• Environmental Engineering Research
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• 제24권2호
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• pp.238-245
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• 2019

This study investigated the characteristic of aerobic granular sludge (AGS) process to treat the sewage having low carbon/nitrogen ratio (Biochemical oxygen demand ($BOD_5$):Total nitrogen (T-N), 4.5:1) in sequencing batch reactor (SBR). The removal efficiency of $BOD_5$, suspended solid (SS), T-N and phosphorus ($PO_4{^{3-}}$-P) were 92.6%, 64.3% and 90.1%. Concentration and size of AGS were changed in proportion to the organic matters and nitrogen concentration of the influent (Concentration and size of AGS: 1,700-3,000 mg/L, 0.5-1.0 mm). Mixed liquor suspended solid (MLSS) also changed with the concentration of AGS (MLSS: 2,000-3,500 mg/L). When the settling time was shortened from 15 min to 10 min, size and shape of AGS were maintained (Size of AGS: 1.0-1.5 mm). In addition, the concentration of AGS and MLSS increased (Concentration of AGS: 3,500 mg/L, MLSS: 4,000 mg/L). Concentration, size and shape of AGS were affected the settling time of the reactor more than the concentration of organic matter and nitrogen in the influent. In the results of removal efficiency and changes in AGS, we confirmed that the SBR process using AGS can be used to treat the sewage having low carbon/nitrogen ratio by applying short settling time.

• Journal of Pharmaceutical Investigation
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• 제40권6호
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• pp.367-372
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• 2010

Rabeprazole sodium (RPN) is known to be very unstable at acidic condition or some acidic pharmaceutical excipients such as acrylic acid polymer (carbomer 934) with carboxylic acids. Thus, degradation mechanism of binary blends of rabeprazole with pharmaceutical excipients in a solid state without using solvents at three different ratios (3:1, 1:1 and 1:3) was investigated using Fourier transform infrad (FTIR) spectroscopy. Alkalizer (MgO), neutral hydroxypropymethylcellulose (HPMC 4000) were also tested for comparison. The binary blends were stored under accelerated conditions ($40^{\circ}C$/75% relative humidity) for two weeks. The concentration of thioether rabeprazole from the binary blends with acidic carbomer 934 increased as the rabeprazole concentration decreased. In addition, the degradation half-life of rabeprazole as well as the relative peak area ratios obtained from FTIR spectra of S=O stretching at $1094.1\;cm^{-1}$ decreased consistently as the fraction of carbomer 934 increased due to its sensitivity between the basic benzimidazole nitrogen and carboxylic acid group of carbomer 934. The physical appearance also turned into strong brown color in the presence of carbomer 934. In contrast, there were no significant changes in the degradation kinetics of rabeprazole with MgO and HPMC 4000 in a solid state. This present study demonstrated that the solid-state compatibility test with the aid of HPLC chromatographic and FTIR spectral analyses could offer a valuable methodology to select suitable pharmaceutical excipients and to elucidate the degradation mechanism of RPN for drug formulations at the early formulation stages.

• Journal of Applied Biological Chemistry
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• 제57권3호
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• pp.197-203
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• 2014

Various parameters such as solvent selection, concentration, solid/liquid ratio, soaking time, temperature, stationary, shaking conditions, and repeated extractions were investigated in order to determine the optimum extraction conditions of ${\beta}$-glucosidase from bagasse fermented by mixed culture of Aspergillus niger NRC 7A and Aspergillus oryzae NRRL 447. Among various solvents tested, non ionic detergents gave the best results than the inorganic or organic salt solutions and distilled water. The optimum conditions for extraction of ${\beta}$-glucosidase were 30 min soaking time at $40^{\circ}C$ under shaking condition at 150 rpm, with solid/liquid ratio 1:15 (w/v), which yielded $2882.74{\pm}95.52U/g$ fermented culture (g fc) of enzyme activity. With repeated washes under the above optimum conditions, the results showed that enzyme extracted in the $1^{st}$ and $2^{nd}$ washes represents about 90% of the total activity.

• 한국산학기술학회논문지
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• 제2권2호
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• pp.19-23
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• 2001

본 연구에서는 축산에서 발생하는 분료의 슬러지을 고체와 액체로 분류하는 장치를 개발하기 위한 논문이다. 필터의 재료는 농촌에서 쉽게 구할 수 있는 왕겨를 사용하였으며 제안한 고액 분리기의 성능을 실험적으로 도출하였고, 필터두께와 왕겨 입겨 입자크기 및 주입 압력에 따른 토출량으로 나타냈다. 이 연구에서 고액 분리기의 최적 설계조건을 구한 후 이를 토대로 왕겨를 이용한 고액 분리기의 성능을 평가한 결과 좋은 성능을 얻었다.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.465-470
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• 2006

An experimental investigation is carried out to study 2-phase vertically upward hydraulic transport of solid particles by water and non-Newtonian fluids in a slim hole concentric annulus with rotation of the inner cylinder. Rheology of particulate suspensions in viscoelastic fluids is of importance in many applications such as particle removal from surfaces, transport of proppants in fractured reservoir and cleaning of drilling holes, etc. In this study a clear acrylic pipe was used in order to observe the movement of solid particles. Annular fluid velocities varied from 0.2 m/s to 3.0 m/s. Pressure drops and average flow rate and particle rising velocity are measured. For both water and 0.2% CMC solutions, the higher the concentration of the solid particles is, the larger the pressure gradients become.

• 한국연소학회:학술대회논문집
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• 대한연소학회 2003년도 제27회 KOSCO SYMPOSIUM 논문집
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• pp.167-173
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• 2003

An experimental study on the behavior of droplets impinging on a solid flat surface was carried out in the present study. Breakup of a liquid droplet impinging on a solid surface has been investigated experimentally for various fuels with different properties. The fuel temperature and incident angle were chosen as major parameters. And fuel temperature and incident angle varied in the range from $-20^{\circ}C$ to $30^{\circ}C$ and from $30^{\circ}$ to $60^{\circ}$, respectively, were investigated. It was found that the variation of fuel temperature influences upon droplet mean diameter which were bounced out from the solid surface. As the increases of incident angle, the break-out mass flow rate increases. This causes the decrease of liquid film flow rate. The larger incident angle gives less liquid film flow rate.

• 한국식품과학회지
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• 제34권1호
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• pp.1-7
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• 2002

여름무 품종별 무의 절임 특성을 알아보기 위해, 절임 염수(소금 농도: 15%) $(2{\times}2{\times}2\;cm)$로 절단한 3 품종('백봉', '관동', '92343')의 여름 무를 2배의 절임 염수에 넣어 $15^{\circ}C$에서 절이면서 절임 중 깍두기 무의 염도, 중량, 수분함량, 가용성 고형물 함량 및 경도(TPA)를 알아보았다. 3 품종의 깍뚜기 무 모두 절임 시간이 경과 될수록 염도, 가용성 고형물 함량은 증가하였으며, 중량 및 수분함량은 감소하는 경향을 나타내었고, texture analyser에 의한 경도는 감소하는 경향을 나타내었다. 깍두기 무의 소금 농도가 3%에 달할 때까지의 절임 염수의 소금 농도에 따른 최적 절임 시간은 '백봉'은 3시간, '관동' 및 '92343'은 4시간이 적당하였다. 절이는 동안 중량 감소율은 '백봉'이 약간 컸고, '관동' 및 '92343'은 비슷하였다. '관동'과 '92343'은 '백봉'에 비해 수분함량이 적었고, 가용성 고형물 함량이 많았으며 경도가 높았으며 '백봉'은 수분함량이 많고 가용성 고형물 함량이 적었고 경도가 낮았다. 한편, 절임무의 계절별 특성을 알아보고자 '백봉' 및 '백관' 2 품종에 대해 10% 또는 15%의 절임 염수에서 절이는 동안의 깍두기 무중의 염도가 3%에 달하였을때의 절임무 특성을 계절별로 알아본 결과, '백봉'은 염침투 속도, 중량 감소정도, 가용성 고형물 함량 및 경도가, '백광'은 염침투 속도, 중량 감소정도 및 경도가 가을이 봄 및 여름에 비해 높게 나타났으며, 수분 함량은 두 품종 모두 봄 및 여름이 가을에 비해 높게 나타났다.

• 한국식품영양과학회지
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• 제25권5호
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• pp.824-830
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• 1996

삼투건조의 여러 가지 가공변수 중 설탕용액의 농도를 달리하고 침지시간, 침지온도를 달리하여 삼투건조를 행하여 물질이동을 나타내는 Solid Gain(SG), Weight Reduction(WR), Moisture Loss(ML) 등을 조사하여 물질이동특성을 알아 보고자 하였다. 온도와 농도 시간에 따른 수분의 이동과 용질의 이동을 확산식으로 평가하였다. 색차의 변화((equation omitted)E)는 $60^{\circ}C에서만$ 높은 값을 보여 갈변이 심해짐을 확인할 수 있었으며, 높은 온도에서는 낮은 농도에서 처리가 더 큰 (equation omitted)E값을 나타내었고, 낮은 온도에서는 농도에 따라서 큰차이를 나타내지 않았다. SG은 농도가 증가할수록 설탕의 흡수가 많아져 증가하였으며, WR 또한 고농도에서 무게감소가 많이 이루어지고 저농도에서는 낮은 값을 보여 설탕농도가 높아질수록 많은 양의 무게감소가 이루어짐을 알 수 있었다. ML는 저농도 보다는 고농도에서 빠른 증가가 일어나 건조가 빠르게 진행됨을 알 수 있었으며 수분 함량은 삼투농도가 높을수록 수분 함량이 점차 낮아져 삼투처리로 건조가 이루어짐을 화인할 수 있었다. 수분의 이동에 따른 확산계수는 같은 온도, 같은 농도에서 각각 농도나 온도의 증가시 높은 값을 가져 확산이 빠르게 일어남을 알 수 있었다. 용질의 이동에 따른 확산계수는 온도의 증가에 따라 증가하는 경향을 보였으며, 농도의 영향에 있어서는 $20^{\circ}C에서는$ 농도의 증가에 따라 증가함을 보였으나 $40^{\circ}C와$ $60^{\circ}C에서는$ 감소하는 경향을 보였다. 확산계수에 대한 온도의 영향을 Arrhenius 식에 적합시켜 본 결과, 5% 유의 수준에서 수분의 이동은 60 。Brix, 용질의 경우는 40。Brix의 농도에서만 적합하다고 할 수 있었다. 수분과 용질의 확산에 있어서 낮은 농도인 20。Brix에서는 높은 활성화 에너지를 보였으며 상대적으로 고농도인 40 Brix와 60 。Brix에서는 낮은 활성화 에너지를 보여 확산이 쉽게 일어남을 알 수 있었다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제22권5호
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• pp.89-97
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• 2017

In this study, we evaluated effect of particle size on arsenic solid-state speciation and bioaccessibility in soils highly contaminated with arsenic from smelting and mining. Soils were partitioned into six particle size fractions ($2000-500{\mu}m$, $500-250{\mu}m$, $250-150{\mu}m$, $150-75{\mu}m$, $75-38{\mu}m$, <$38{\mu}m$), and arsenic solid-state speciation and bioaccessibility were characterized in each particle size fraction. Arsenic solid-state speciation was characterized via sequential extraction and XRD analysis, and arsenic bioaccessibility was evaluated by SBRC (Solubility Bioaccessibility Research Consortium) method. In smelter site soil, arsenic was mainly present as arsenic bound to amorphous iron oxides. Fine particle size fractions showed higher arsenic concentration, but lower arsenic bioaccessibility. On the other hand, arsenic in mine site soil showed highest concentration in largest particle size fraction ($2000-500{\mu}m$), while higher bioaccessibility was observed in smaller particle size fractions. Arsenic in mine site soil was mainly present as arsenolite ($As_2O_3$) phase, which seemed to affect the distribution of arsenic and arsenic bioaccessibility in different particle size fractions of the mine soil.

• Bulletin of the Korean Chemical Society
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• 제27권10호
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• pp.1557-1561
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• 2006

The use of chemically modified silica-salen$(NEt_2)_2$ was studied for the separation and concentration of the metal ions from an aqueous solution by a solid phase extraction. After the salen(NEt2)2 was synthesized, it was chemically bonded to silica gel by a diazonium coupling reaction. The adsorption capacities and binding constants were obtained with respect to Cu(II), Mn(II), Pb(II) and Zn(II) by a graphical method. Some experimental conditions were optimized for the determination of the trace elements. After the silica-salen(NEt2)2 was pulverized in a sample solution of which the pH was adjusted, the solution was stirred to pre-concentrate the metal ions. The metal ions adsorbed were desorbed with nitric acid solution. And the concentrated analytes were determined by a flame AAS. The method proposed here was so rarely influenced by a sample matrix that the procedure was applied to 3 types of water samples. The reproducible results of less than 10% RSD were obtained at the concentration level of ca. 100 ng/mL and the recoveries of 95-109% were obtained in the spiked samples in which given amounts of analytes were added.